net/sched/act_mpls.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 /* Copyright (C) 2019 Netronome Systems, Inc. */
   3
   4 #include <linux/if_arp.h>
   5 #include <linux/init.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/mpls.h>
   9 #include <linux/rtnetlink.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/tc_act/tc_mpls.h>
  12 #include <net/mpls.h>
  13 #include <net/netlink.h>
  14 #include <net/pkt_sched.h>
  15 #include <net/pkt_cls.h>
  16 #include <net/tc_act/tc_mpls.h>
  17 #include <net/tc_wrapper.h>
  18
  19 static struct tc_action_ops act_mpls_ops;
  20
  21 #define ACT_MPLS_TTL_DEFAULT    255
  22
  23 static __be32 tcf_mpls_get_lse(struct mpls_shim_hdr *lse,
  24                                struct tcf_mpls_params *p, bool set_bos)
  25 {
  26         u32 new_lse = 0;
  27
  28         if (lse)
  29                 new_lse = be32_to_cpu(lse->label_stack_entry);
  30
  31         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET) {
  32                 new_lse &= ~MPLS_LS_LABEL_MASK;
  33                 new_lse |= p->tcfm_label << MPLS_LS_LABEL_SHIFT;
  34         }
  35         if (p->tcfm_ttl) {
  36                 new_lse &= ~MPLS_LS_TTL_MASK;
  37                 new_lse |= p->tcfm_ttl << MPLS_LS_TTL_SHIFT;
  38         }
  39         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET) {
  40                 new_lse &= ~MPLS_LS_TC_MASK;
  41                 new_lse |= p->tcfm_tc << MPLS_LS_TC_SHIFT;
  42         }
  43         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET) {
  44                 new_lse &= ~MPLS_LS_S_MASK;
  45                 new_lse |= p->tcfm_bos << MPLS_LS_S_SHIFT;
  46         } else if (set_bos) {
  47                 new_lse |= 1 << MPLS_LS_S_SHIFT;
  48         }
  49
  50         return cpu_to_be32(new_lse);
  51 }
  52
  53 TC_INDIRECT_SCOPE int tcf_mpls_act(struct sk_buff *skb,
  54                                    const struct tc_action *a,
  55                                    struct tcf_result *res)
  56 {
  57         struct tcf_mpls *m = to_mpls(a);
  58         struct tcf_mpls_params *p;
  59         __be32 new_lse;
  60         int ret, mac_len;
  61
  62         tcf_lastuse_update(&m->tcf_tm);
  63         bstats_update(this_cpu_ptr(m->common.cpu_bstats), skb);
  64
  65         /* Ensure 'data' points at mac_header prior calling mpls manipulating
  66          * functions.
  67          */
  68         if (skb_at_tc_ingress(skb)) {
  69                 skb_push_rcsum(skb, skb->mac_len);
  70                 mac_len = skb->mac_len;
  71         } else {
  72                 mac_len = skb_network_header(skb) - skb_mac_header(skb);
  73         }
  74
  75         ret = READ_ONCE(m->tcf_action);
  76
  77         p = rcu_dereference_bh(m->mpls_p);
  78
  79         switch (p->tcfm_action) {
  80         case TCA_MPLS_ACT_POP:
  81                 if (skb_mpls_pop(skb, p->tcfm_proto, mac_len,
  82                                  skb->dev && skb->dev->type == ARPHRD_ETHER))
  83                         goto drop;
  84                 break;
  85         case TCA_MPLS_ACT_PUSH:
  86                 new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb_protocol(skb, true)));
  87                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len,
  88                                   skb->dev && skb->dev->type == ARPHRD_ETHER))
  89                         goto drop;
  90                 break;
  91         case TCA_MPLS_ACT_MAC_PUSH:
  92                 if (skb_vlan_tag_present(skb)) {
  93                         if (__vlan_insert_inner_tag(skb, skb->vlan_proto,
  94                                                     skb_vlan_tag_get(skb),
  95                                                     ETH_HLEN) < 0)
  96                                 goto drop;
  97
  98                         skb->protocol = skb->vlan_proto;
  99                         __vlan_hwaccel_clear_tag(skb);
 100                 }
 101
 102                 new_lse = tcf_mpls_get_lse(NULL, p, mac_len ||
 103                                            !eth_p_mpls(skb->protocol));
 104
 105                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, 0, false))
 106                         goto drop;
 107                 break;
 108         case TCA_MPLS_ACT_MODIFY:
 109                 if (!pskb_may_pull(skb,
 110                                    skb_network_offset(skb) + MPLS_HLEN))
 111                         goto drop;
 112                 new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
 113                 if (skb_mpls_update_lse(skb, new_lse))
 114                         goto drop;
 115                 break;
 116         case TCA_MPLS_ACT_DEC_TTL:
 117                 if (skb_mpls_dec_ttl(skb))
 118                         goto drop;
 119                 break;
 120         }
 121
 122         if (skb_at_tc_ingress(skb))
 123                 skb_pull_rcsum(skb, skb->mac_len);
 124
 125         return ret;
 126
 127 drop:
 128         qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
 129         return TC_ACT_SHOT;
 130 }
 131
 132 static int valid_label(const struct nlattr *attr,
 133                        struct netlink_ext_ack *extack)
 134 {
 135         const u32 *label = nla_data(attr);
 136
 137         if (nla_len(attr) != sizeof(*label)) {
 138                 NL_SET_ERR_MSG_MOD(extack, "Invalid MPLS label length");
 139                 return -EINVAL;
 140         }
 141
 142         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 143                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 144                 return -EINVAL;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 151         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 152         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 153         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_BINARY,
 154                                                          valid_label),
 155         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 156         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 157         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 158 };
 159
 160 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 161                          struct nlattr *est, struct tc_action **a,
 162                          struct tcf_proto *tp, u32 flags,
 163                          struct netlink_ext_ack *extack)
 164 {
 165         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 166         bool bind = flags & TCA_ACT_FLAGS_BIND;
 167         struct nlattr *tb[TCA_MPLS_MAX + 1];
 168         struct tcf_chain *goto_ch = NULL;
 169         struct tcf_mpls_params *p;
 170         struct tc_mpls *parm;
 171         bool exists = false;
 172         struct tcf_mpls *m;
 173         int ret = 0, err;
 174         u8 mpls_ttl = 0;
 175         u32 index;
 176
 177         if (!nla) {
 178                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 179                 return -EINVAL;
 180         }
 181
 182         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 183         if (err < 0)
 184                 return err;
 185
 186         if (!tb[TCA_MPLS_PARMS]) {
 187                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 188                 return -EINVAL;
 189         }
 190         parm = nla_data(tb[TCA_MPLS_PARMS]);
 191         index = parm->index;
 192
 193         /* Verify parameters against action type. */
 194         switch (parm->m_action) {
 195         case TCA_MPLS_ACT_POP:
 196                 if (!tb[TCA_MPLS_PROTO]) {
 197                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 198                         return -EINVAL;
 199                 }
 200                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 201                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 202                         return -EINVAL;
 203                 }
 204                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 205                     tb[TCA_MPLS_BOS]) {
 206                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 207                         return -EINVAL;
 208                 }
 209                 break;
 210         case TCA_MPLS_ACT_DEC_TTL:
 211                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 212                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 213                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 214                         return -EINVAL;
 215                 }
 216                 break;
 217         case TCA_MPLS_ACT_PUSH:
 218         case TCA_MPLS_ACT_MAC_PUSH:
 219                 if (!tb[TCA_MPLS_LABEL]) {
 220                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 221                         return -EINVAL;
 222                 }
 223                 if (tb[TCA_MPLS_PROTO] &&
 224                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 225                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 226                         return -EPROTONOSUPPORT;
 227                 }
 228                 /* Push needs a TTL - if not specified, set a default value. */
 229                 if (!tb[TCA_MPLS_TTL]) {
 230 #if IS_ENABLED(CONFIG_MPLS)
 231                         mpls_ttl = net->mpls.default_ttl ?
 232                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 233 #else
 234                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 235 #endif
 236                 }
 237                 break;
 238         case TCA_MPLS_ACT_MODIFY:
 239                 if (tb[TCA_MPLS_PROTO]) {
 240                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 241                         return -EINVAL;
 242                 }
 243                 break;
 244         default:
 245                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 246                 return -EINVAL;
 247         }
 248
 249         err = tcf_idr_check_alloc(tn, &index, a, bind);
 250         if (err < 0)
 251                 return err;
 252         exists = err;
 253         if (exists && bind)
 254                 return 0;
 255
 256         if (!exists) {
 257                 ret = tcf_idr_create(tn, index, est, a,
 258                                      &act_mpls_ops, bind, true, flags);
 259                 if (ret) {
 260                         tcf_idr_cleanup(tn, index);
 261                         return ret;
 262                 }
 263
 264                 ret = ACT_P_CREATED;
 265         } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 266                 tcf_idr_release(*a, bind);
 267                 return -EEXIST;
 268         }
 269
 270         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 271         if (err < 0)
 272                 goto release_idr;
 273
 274         m = to_mpls(*a);
 275
 276         p = kzalloc(sizeof(*p), GFP_KERNEL);
 277         if (!p) {
 278                 err = -ENOMEM;
 279                 goto put_chain;
 280         }
 281
 282         p->tcfm_action = parm->m_action;
 283         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 284                                              ACT_MPLS_LABEL_NOT_SET;
 285         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 286                                        ACT_MPLS_TC_NOT_SET;
 287         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 288                                          mpls_ttl;
 289         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 290                                          ACT_MPLS_BOS_NOT_SET;
 291         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 292                                              htons(ETH_P_MPLS_UC);
 293
 294         spin_lock_bh(&m->tcf_lock);
 295         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 296         p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 297         spin_unlock_bh(&m->tcf_lock);
 298
 299         if (goto_ch)
 300                 tcf_chain_put_by_act(goto_ch);
 301         if (p)
 302                 kfree_rcu(p, rcu);
 303
 304         return ret;
 305 put_chain:
 306         if (goto_ch)
 307                 tcf_chain_put_by_act(goto_ch);
 308 release_idr:
 309         tcf_idr_release(*a, bind);
 310         return err;
 311 }
 312
 313 static void tcf_mpls_cleanup(struct tc_action *a)
 314 {
 315         struct tcf_mpls *m = to_mpls(a);
 316         struct tcf_mpls_params *p;
 317
 318         p = rcu_dereference_protected(m->mpls_p, 1);
 319         if (p)
 320                 kfree_rcu(p, rcu);
 321 }
 322
 323 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 324                          int bind, int ref)
 325 {
 326         unsigned char *b = skb_tail_pointer(skb);
 327         struct tcf_mpls *m = to_mpls(a);
 328         struct tcf_mpls_params *p;
 329         struct tc_mpls opt = {
 330                 .index    = m->tcf_index,
 331                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 332                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 333         };
 334         struct tcf_t t;
 335
 336         spin_lock_bh(&m->tcf_lock);
 337         opt.action = m->tcf_action;
 338         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 339         opt.m_action = p->tcfm_action;
 340
 341         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 342                 goto nla_put_failure;
 343
 344         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 345             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 346                 goto nla_put_failure;
 347
 348         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 349             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 350                 goto nla_put_failure;
 351
 352         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 353                 goto nla_put_failure;
 354
 355         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 356             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 357                 goto nla_put_failure;
 358
 359         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 360                 goto nla_put_failure;
 361
 362         tcf_tm_dump(&t, &m->tcf_tm);
 363
 364         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 365                 goto nla_put_failure;
 366
 367         spin_unlock_bh(&m->tcf_lock);
 368
 369         return skb->len;
 370
 371 nla_put_failure:
 372         spin_unlock_bh(&m->tcf_lock);
 373         nlmsg_trim(skb, b);
 374         return -EMSGSIZE;
 375 }
 376
 377 static int tcf_mpls_offload_act_setup(struct tc_action *act, void *entry_data,
 378                                       u32 *index_inc, bool bind,
 379                                       struct netlink_ext_ack *extack)
 380 {
 381         if (bind) {
 382                 struct flow_action_entry *entry = entry_data;
 383
 384                 switch (tcf_mpls_action(act)) {
 385                 case TCA_MPLS_ACT_PUSH:
 386                         entry->id = FLOW_ACTION_MPLS_PUSH;
 387                         entry->mpls_push.proto = tcf_mpls_proto(act);
 388                         entry->mpls_push.label = tcf_mpls_label(act);
 389                         entry->mpls_push.tc = tcf_mpls_tc(act);
 390                         entry->mpls_push.bos = tcf_mpls_bos(act);
 391                         entry->mpls_push.ttl = tcf_mpls_ttl(act);
 392                         break;
 393                 case TCA_MPLS_ACT_POP:
 394                         entry->id = FLOW_ACTION_MPLS_POP;
 395                         entry->mpls_pop.proto = tcf_mpls_proto(act);
 396                         break;
 397                 case TCA_MPLS_ACT_MODIFY:
 398                         entry->id = FLOW_ACTION_MPLS_MANGLE;
 399                         entry->mpls_mangle.label = tcf_mpls_label(act);
 400                         entry->mpls_mangle.tc = tcf_mpls_tc(act);
 401                         entry->mpls_mangle.bos = tcf_mpls_bos(act);
 402                         entry->mpls_mangle.ttl = tcf_mpls_ttl(act);
 403                         break;
 404                 case TCA_MPLS_ACT_DEC_TTL:
 405                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"dec_ttl\" option is used");
 406                         return -EOPNOTSUPP;
 407                 case TCA_MPLS_ACT_MAC_PUSH:
 408                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"mac_push\" option is used");
 409                         return -EOPNOTSUPP;
 410                 default:
 411                         NL_SET_ERR_MSG_MOD(extack, "Unsupported MPLS mode offload");
 412                         return -EOPNOTSUPP;
 413                 }
 414                 *index_inc = 1;
 415         } else {
 416                 struct flow_offload_action *fl_action = entry_data;
 417
 418                 switch (tcf_mpls_action(act)) {
 419                 case TCA_MPLS_ACT_PUSH:
 420                         fl_action->id = FLOW_ACTION_MPLS_PUSH;
 421                         break;
 422                 case TCA_MPLS_ACT_POP:
 423                         fl_action->id = FLOW_ACTION_MPLS_POP;
 424                         break;
 425                 case TCA_MPLS_ACT_MODIFY:
 426                         fl_action->id = FLOW_ACTION_MPLS_MANGLE;
 427                         break;
 428                 default:
 429                         return -EOPNOTSUPP;
 430                 }
 431         }
 432
 433         return 0;
 434 }
 435
 436 static struct tc_action_ops act_mpls_ops = {
 437         .kind           =       "mpls",
 438         .id             =       TCA_ID_MPLS,
 439         .owner          =       THIS_MODULE,
 440         .act            =       tcf_mpls_act,
 441         .dump           =       tcf_mpls_dump,
 442         .init           =       tcf_mpls_init,
 443         .cleanup        =       tcf_mpls_cleanup,
 444         .offload_act_setup =    tcf_mpls_offload_act_setup,
 445         .size           =       sizeof(struct tcf_mpls),
 446 };
 447
 448 static __net_init int mpls_init_net(struct net *net)
 449 {
 450         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 451
 452         return tc_action_net_init(net, tn, &act_mpls_ops);
 453 }
 454
 455 static void __net_exit mpls_exit_net(struct list_head *net_list)
 456 {
 457         tc_action_net_exit(net_list, act_mpls_ops.net_id);
 458 }
 459
 460 static struct pernet_operations mpls_net_ops = {
 461         .init = mpls_init_net,
 462         .exit_batch = mpls_exit_net,
 463         .id   = &act_mpls_ops.net_id,
 464         .size = sizeof(struct tc_action_net),
 465 };
 466
 467 static int __init mpls_init_module(void)
 468 {
 469         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 470 }
 471
 472 static void __exit mpls_cleanup_module(void)
 473 {
 474         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 475 }
 476
 477 module_init(mpls_init_module);
 478 module_exit(mpls_cleanup_module);
 479
 480 MODULE_SOFTDEP("post: mpls_gso");
 481 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
 482 MODULE_LICENSE("GPL");
 483 MODULE_DESCRIPTION("MPLS manipulation actions");